The following section addresses habits and lifestyle modifi cation including tobacco use, alcohol abuse, obesity, and physical inactivity. The data that support these measures in secondary stroke preven- tion are scarce. Nonetheless, given the strong epide- miological association between these risk factors and stroke, and their adverse impact on other condi- tions, it is reasonable to extrapolate the data from primary prevention studies. In addition, it appears as if the initiation of these stroke prevention strate- gies while the patient is still in the hospital increases adherence [81,82].
Summary of recommendations
1 More rigorous control of BP and lipids should be considered in patients with diabetes (Class IIa, Level B).
2 Although all major classes of antihypertensives are suitable for the control of BP, most patients will require more than 1 agent. ACE-Is and ARBs are more effective in reducing the progression of renal disease and are recommended as fi rst-choice medications for patients with DM (Class I, Level A).
3 Glucose control is recommended to near-
normoglycemic levels among diabetics with ischemic stroke or TIA to reduce microvascular complications (Class I, Level A).
4 The goal for HbA1C should be ≤7% (Class IIa, Level B).
Example Case, cont’d.
This patient had newly diagnosed DM. She was referred to a comprehensive diabetes program for dietary and exercise counseling and for screening for kidney and retinal disease. In addition to tight control of hypertension and dyslipidemia, she was treated with oral hypoglycemic agents with a goal HbA1C of ≤7. Given that she was overweight, she was started on metformin.
sibility that it may be benefi cial to prevent macro- vascular complications including stroke, it is reasonable to target an HbA1C level of ≤7%.
Tobacco use
About 21% of all US adults are current smokers [1];
438,000 individuals die of smoking-related diseases each year, a third of these deaths are due to vascular events, and the annual health-related cost of smoking is estimated at $167 billion [84]. The epidemiologi- cal association of cigarette smoking and stroke is established and suffi cient to infer a causal relation- ship. A meta-analysis of 32 studies found a relative risk for ischemic stroke of 1.9 and for subarachnoid hemorrhage (SAH) of 2.9 [85]. Subsequent studies have validated these results: the British Doctors Study found a relative risk of 1.31 for ischemic stroke and 2.14 for SAH in men [86], and a Finnish study reported an increased risk in SAH in men (RR 2.4, 95% CI 1.6–3.7) and women (RR 2.5, 95% CI 1.5–4.1) [87]. The combination of oral contracep- tives and smoking is associated with greater risk [88]. The association between smoking and intrace- rebral hemorrhage has not been as well established [85]. Stroke-related mortality is also increased in smokers (RR 2.5, P < 0.001) [89]. There is a clear dose relationship between the daily number of ciga- rettes consumed and both stroke incidence and stroke mortality [86,90,91].
Smoking cessation results in a decreased risk of a fi rst stroke to the level of nonsmokers within 2–5 years [92,93] as well as in a decrease in stroke-related mortality [94], which justifi es efforts to enhance tobacco cessation. That more effort is needed in this area is exemplifi ed by the fi ndings of a national survey in which cigarette smoking was continued by 18% of individuals who had experienced a previous stroke or MI [95]. Nicotine replacement, social support, and skills training are the recommended interventions to promote smoking cessation [96].
Alcohol consumption
The effects of alcohol on stroke risk is related to the amount consumed. Alcohol consumption is typi- cally described in number of drinks. One drink is commonly defi ned as 14 g of alcohol, 12 oz of beer, 5 oz of wine, or 1.5 oz of hard liquor [97].
Although excessive alcohol use and binge drink- ing results in an increase in all vascular events, it is now becoming clear that light to moderate con- sumption is protective. A meta-analysis of over 1 million subjects in 34 studies found a “J”-shaped relationship between the amount of alcohol and
mortality. Light to moderate use of 0.5–2 drinks a day was associated with an 18% reduction in total mortality driven by a decline in vascular events [98].
That this is independent of the possible interaction with other vascular risk factors is highlighted by the fi nding of a decrease in MI with one to two drinks a day in men who already followed a healthy lifestyle (healthy diet, exercise, normal weight, and no smoking) [99]. The “J”-shaped relationship between the amount of alcohol and stroke risk has been reported by multiple studies. A meta-analysis of 35 studies found that compared with nondrinkers, the consumption of <1 drink per day was associated with a reduced ischemic stroke risk (RR 0.8), 1–2 drinks per day with an RR of 0.72, 2–5 drinks per day with an RR of 0.96, and >5 drinks per day increased the risk (RR1.69) [100]. In the Northern Manhattan Stroke Study, the benefi cial effects of moderate drinking and the adverse outcome with heavy drinking were confi rmed for various ethnic groups [101,102]. Although the consensus is that the specifi c alcoholic beverage is less important than the amount of alcohol ingested [103], some have sug- gested that red wine may have added benefi ts [104].
The benefi cial effects of moderate drinking appear to be multifactorial and include elevation of HDL [105], reduction in plasma viscosity [106], decrease in infl ammatory markers [107], decreased platelet aggregation [108], and interestingly, enhancement of insulin sensitivity, which may result in decreased postprandial glucose changes [109]. In addition, fl a- vonoids and resveratrol contained in red wine may have benefi cial effects [110]. The adverse events of large doses of alcohol are mediated through hyper- tension, arrhythmias, and cardiomyopathy
Obesity
Obesity, characterized by excess body fat, is defi ned as a BMI of ≥30 kg/m2, whereas overweight is defi ned as a BMI between 25 and 29.9 kg/m2 [111]. Two- thirds of the adult population in the United States is either overweight or obese, and this proportion appears to be increasing [112]. It is estimated that by 2015, there will be 1.5 billion overweight and obese individuals worldwide [113].
Although obesity is closely related to hyperten- sion, diabetes, and dyslipidemia, it is an indepen- dent risk factor for stroke. The association between
obesity and stroke in men has been confi rmed by various studies [114,115]. The Physician’s Health Study found that compared with individuals with a BMI of <23 kg/m2, obese men had a relative risk of stroke of 2 (95% CI 1.48–2.71), and estimated that each unit increase of BMI resulted in a 6% increase in risk [114]. The association between obesity and stroke in women is less consistent. In the Women’s Health Study, obese women had an HR of 1.5 (1.16–
1.94) compared with individuals with normal weight [116], and in the Nurses’ Health Study, there was a greater than 2-fold increase in stroke risk for BMI
≥32 kg/m2 compared with <21 kg/m2 [117], but
other reports were unable to document this associa- tion [118–121]. Abdominal obesity is more closely related to the risk of stroke than general obesity.
Waist circumference, a useful measure of abdominal obesity, is defi ned as >102 cm (40 inches) in men
and >88 cm (35 inches) in women. It was closely
related to stroke risk in the Northern Manhattan Stroke Study [122]. The mechanisms by which obesity is independently associated with an increased risk of stroke are incompletely understood but may involve prothrombotic [123] and infl ammatory [124] states.
Weight reduction interventions include dieting, exercise, behavioral modifi cation therapy, pharma- cotherapy, and surgical or laparoscopic approaches.
Although no trials have assessed the impact of weight reduction on stroke risk [125], it is also clear that reductions of 5–15% of baseline weight result in better control of hypertension, diabetes, and dyslip- idemia [126]. Fruit- and vegetable-rich diets, such as the Mediterranean diet, reduce vascular events [127].
Physical activity
The levels of physical activity have remained stable for adults in the United States in the last decade [128], and only about half of all adults engage in frequent regular vigorous exercise; this proportion is lower for minorities and the elderly, and youth engagement in physical activity is poor [1].
A recent meta-analysis of 18 cohort and 5 case- control studies found a protective effect of physical activity on stroke. Compared with low levels of activity, highly active individuals had a signifi cant decrease in stroke incidence and mortality (RR 0.73, 95% CI 0.67–0.79); the effect was still present but of
lesser magnitude for individuals who engage in moderate intensity activity (RR 0.80, 95% CI 0.74–
0.86). This effect was seen for both ischemic and hemorrhagic strokes [129]. The protective effect of physical activity has also been documented in older individuals with vascular risk factors [130] and in different ethnic groups [131].
The benefi cial effects of physical activity are medi- ated through various factors, including BP reduc- tion [132], improved glycemic control [133] and lipidic profi les [134], weight reduction, and decreased viscosity [135] and platelet aggregability [136].
Summary of recommendations
1 All ischemic stroke or TIA patients who have smoked in the past year should be strongly encouraged not to smoke (Class I, Level C).
2 Counseling, nicotine products, and oral smoking cessation medications have been found to be effective for smokers (Class IIa, Level B).
3 Avoid environmental smoke (Class IIa, Level C).
4 Patients with prior ischemic stroke or TIA who are heavy drinkers should eliminate or reduce their consumption of alcohol (Class I, Level A).
5 Light to moderate levels of ≤2 drinks per day for men and 1 drink per day for nonpregnant women may be considered (Class IIb, Level C).
6 Weight reduction may be considered for all overweight ischemic stroke or TIA patients to maintain the goal of a BMI of 18.5–24.9 kg/m2 and a waist circumference of <35 inches for women and
<40 inches for men. Clinicians should encourage weight management through an appropriate balance of caloric intake, physical activity, and behavioral counseling (Class IIb, Level C).
7 For those with ischemic stroke or TIA who are capable of engaging in physical activity, at least 30 minutes of moderate-intensity physical exercise on most days may be considered to reduce risk factors and comorbid conditions that increase the likelihood of recurrence of stroke. For those with disability after ischemic stroke, a supervised therapeutic exercise regimen is recommended (Class IIb, Level C).